Oil extraction from shale



{35"8- 1 R. A. FINDLAY OIL EXTRACTION FROM SHALE Filed Dec. 20, 1950 v INVENTOR. RA FINDLAY A 'r roe/vars Patented Aug. 3, 1954 OIL EXTRACTION FROM SHALE Robert A. Findlay, Bartlesville, -kla., assignor to Phillips Petroleum Company, a corporation of Delaware Application December 20, 1950, Serial No. 201,789

Claims. 1

This invention relates to the recovery of shale oilproducts. In one of its aspects the invention relates to the treatment of crushed shale according to a method and in a manner such that oil products are recovered to a maximum extent without incurring any appreciable undesired reactions, e. g. polymerization, destructive pyrolysis, etc.

According to the invention the shale is crushed and made up in slurry form, employing for this purpose a. refractory recycle or other oil, and then passed downwardly through a plate and cap or bubble tray equipped column countercurrently with hot vapors which can be a vaporized portion of the refractory oil employed to make up the aforesaid slurry. As the slurry passes downwardly through the column, from tray to tray, the temperature of the shale therein is gradually increased resulting in vaporization of recoverable oils. Vapors are taken off at points spaced along the column, cooled and condensed. Non-condensed gases or vapors are returned to the tower. Finally the slurry, substantially denuded of its recoverable oils, reaches the locus of introduction of the hot refractory oil; At this stage of its travel down through the tower, the slurry can be heated to a moderate or even a severe cracking temperature for a suitable length of time, if desired, thus recovering additional products, among which may be found the refractory oil to be employedin the method. Progressing down through the bottom portion of the column, the slurry can be subjected to a gas stripping step. Gas for this purpose can be the gas taken overhead from the column before and after treatment in a gas ad- I sorption plant. Spent shale, which is withdrawn from the tower or column, can be filtered and used as fuel, for example, to supply heat to the refractory oil. This use of the spent shale, at its location of treatment is a point of advantage of my method, the principal advantage of which is, as stated, the recovery of shale oil products to a maximum extent without incurring any appreciable undesired reactions. It is apparent that in the method of the invention, the oils are recovered immediately upon their vaporization. The method according to the invention combines in its operational steps the effect of a gradual heating with a solvent extraction effect produced by the recycle of refractory oil. Thus the method according to the invention comprises, in effect, a heat-extraction step. The refractory oil is preferably a highly aromatic recycle stock which can result from normal refinery operations.

The drawing illustrates a specific embodiment of the invention. Referring now to the drawing a refractory .oil, which can be oil recovered and recycled from the oil extraction column, is used to make up a shale slurry in slurry tank I. The characteristics of the recycle oil are to be such that it will not decompose to any undesired products during the shale extraction step of the method and that it will be substantially recoverable from the spent shale before the shale is used as fuel or disposed of in any other manner. Refractory recycle oil will ordinarily contain fractions boiling in the range of from 500 to 900 F. The slurry is pumped from tank I by means of slurry pump 2 through line 3 to oil extraction tower t. The slurry is fed to the top of the tower and is allowed to cascade or flow downwardly therethrough over a plurality of bubble cap trays like 5 and 6 as shown in the drawing. Obviously, tower 4 will contain a large number of trays like trays 5 and B but for sake of simplicity only two trays have been shown. Tower 4 is provided with a plurality of vapor drawoif lines I, 8 and 9 leading to coolers and condensers indicated by I0, I I and I2 in the drawing. Substantially liquefied streams are Withdrawn from Ill, I i and I2 and subjected to gas separation in gas separators I3, I4 and I5 from which liquid product is withdrawn through lines IE, IT, l8 and I9. Non-condensed portions of the vapors entering gas separators I3, I 5, and I5 are returned through lines 2|, 22 and 23 to the tower 4. Any gas which remains uncondensed in tower 4 is finally withdrawn through line 2 and is treated in a gas absorption plant following which the treated gas is returned through line 25 and introduced into the bottom of tower l to act as a stripping and cooling medium for stripping of the spent shale before the said shale is discarded, as above described. The use of the process gas as a stripping gas serves to dilute the decomposition products in the upper portions of the column, thus minimizing undesired polymerization and tar formation. Refractory oil, Which as stated, can be recovered from the process, is passed into heat exchange relationship with the vapors passing through lines I, 8 and 9 to gas separators 53, I4 and I 5 and then is preheated to a temperature in the range of 800 to 1000 F. in heater 26 and introduced through line 21, to tower 4, thus supplying the heat required in the method for the recovery of the oil from the shale.

The column is operated under a pressure in the range of from atmospheric to 300 pounds per square inch and the operation is conducted to maintain a temperature in the hottest portion of the heating section in the range of 700 900 F. depending upon retention time and type of shale chosen. The stripped spent shale is withdrawn from tower *4, through line 28, and then passed through a filter 29 and line 39 to fractionator 5 3| wherein oil separated from the shale is separated into a recycle or gas oil and a heavy oil which aretrecoveredairom the 'f ra'ctiorrator .3! 5 through lines-32 and 33 respectively; i

The filtered spent shale is washed while on the 10 filter 29 with a relatively low boiling hydrocarbon introduced through line 34. The low=boilingchy-. drocarbon containing oil extracted from the shale filter cake fiows via line :35 to flash drumfifi '31 where the low-boiling hydrocarbonisflashed: off as a vapor via line 31. The remaining oil flows via line 38 to line it. The wettfilter cakesis. re-. moved from filter 29 and conveyed to a zone, not shown, where the low-boiling hydrocarbon is' recovered by vaporization. 20

In place. of bubbles-sap equipped -trays in col-v ummA, suitablytsized;shaped and spacedpieces of shale canhe usedrin the column. 4'

In addition to the advantagesalready setout herein;- it isto be noted-especially that operation. according :to this invention willrealize considerable seconomy of heat: as well as coolingv water.- Thus one. skilledin the art will realize from-this. disclosure .lt-hatv-there :is involved -considerable-- economy of heat as well-as cooling-water due to the manner in which the countercurrent heat exa traction step; can :be brought about. "However, as stated, it is part. of the :concept of thisinveni tionthat-the productsas formedare-rapidly removed-thus avoiding". undesirableror secondary. 163,C.tiOnS: T--

Reasonable variation and modification: "are possiblevwithinnthe scopezoi the .foregoing'dis closure andithe appendedclaimszto the inventio1re 1 the essence of Which is; that a method'whereina: slurry-of oil shale-is gradually heated by countercurrent contact WithnhOllzVEtDOlSvOf a refractory oil to graduallyrelease 'fromthe "Sha18:-I'eCDV81'-" able-oil vapors and wherein the said: oil vapors s" are"- recovered immediately as formed has heen'li t provided as herein set-forth :and described. r

I claimrr l. A method for recovering shale oil from 8111871812: which comprises the 'steps of forming a slurry'of shale With-51 refractory oil; 'rDaSSriIlg :saidaslurry downwardlyfin "a fractionation:vessel;;.provided.-e

with lmea'ns- :for effecting intimate contact he-- tweena-slurry :andi vapors-, into mounted-current a heat-e:ttraction-relationship ivith'hot vapor-sot a: refractory .oil, .thus-iorminglvaporous toil products\ tram-the shale and immediately recovering 4 and removing said vaporous oil products, as formed, from said fractionation vessel at a plurality of points to avoid further contact with said hot vapors and condensing said vaporous oil products.

2. A method for the recovery of products from oil shale which comprises passing of a slurry of crushed shale downwardlyiintacounterecurrent heat extract-ion relationship with hot vapors of a refractory oil in a fractionating column provided with means for efiecting intimate contact between slurry. and vapors, the said shale being introduced to a top portion of said tower and ultimatelyz withdrawn-rrrom the bottom thereof; the said refractery.. oil vapors being introduced into a lower portion ef said tower and ultimately, laftenyieldingtupheat and being condensed, withdrawn from thebottom thereof, withdrawing at a plurality of points along said tower immediately as formed vaporous products generrated as a result'of thesaid counter-:currentheatw extraction relationship between-athei saidslurry a; andisaid oil vaporsy and withdrawing said:-slurry.*: v and 1011 irom. the bot-tom of said tovver'.

3. A method-for therecovery of productszfrom'm oil shale-which COIIlPIiSGS'ifihE 'stcpsrof prep aring. a slurry-ofcrushed-shalmwith a. refractory oilcil and passing said slurry to the top of and down-x1 weirdly-through a iractionating rcolumn; introa ducing to alower-porticn-of saiducolummvaporsnl: of a-refrac-toryoil heated to. a temperature. of 800 to 1 000: degrees Fahrenheit,-,- thereby 1 causing counter-currentheateextractionwof said slurry withthe. vapors; of saidheated refractory-oilyrs-r moving at aplurality ofpoints alongrsaid column in immediately as formedavaporous products' gener ated -duling said-1counter-current: heate-extrac; tiony condensing -.said vaporous- .products;-a-and' --i removing- I slurry and .=refractoryoil which: rhas: it) given up: zheatzfrom :the' abottom of said :tower:

4. A method according to claiml3awhereinzthezze slurryzremovedrfrom the bottomcof saidetower is filtered; and thetzoil t thlls recovered :is reheated-2. and re-used as the hot refractoryoila 5. A method-.accordingito claim 13' wherein'thes i refractory oil is. ig ly aromatic "in characters: 1

Reerences:;(3ited;:in theffilezof this pat t UNITED? STATES PATENT 1;-

Nuniberl..:. Name... Date 1,458,983-,-- Kirby. .June 19,.1923/ 2,167,250; Pfirrmann .July 25,1939 w 2,406,810 Day.-: Sept- 3, 1,-94fiw: 2,4313671) Brown DEC. "2', 1.94%. 

1. A METHOD FOR RECOVERING SHALE OIL FROM SHALE WHICH COMPRISES THE STEPS OF FORMING A SLURRY OF SHALE WITH A REFRACTORY OIL; PASSING SAID SLURRY DOWNWARDLY IN A FRACTIONATION VESSEL, PROVIDED WITH MEANS FOR EFFECTING INTIMATE CONTACT BETWEEN SLURRY AND VAPORS, INTO COUNTER-CURRENT HEAT-EXTRACTION RELATIONSHIP WITH HOT VAPORS OF A REFRACTORY OIL, THUS FORMING VAPOROUS OIL PROD- 